This is a recently described rare condition in which ocular disease coexists with progressive neurological deterioration and hearing loss.
This disorder often leads to symptoms in young children. Highly arched feet (pes cavus), unsteady gait (ataxia), stiff muscles (spasticity), hearing loss, and tendon contractures can be seen in the first decade of life. The neurological condition is progressive and most of the symptoms are present by the second and third decades. Speech may become slurred as well. Mental function is usually normal.
Cataracts may be seen by the age of 10 years and usually progress to cause significant visual problems by the third decade. The retina in the eye deteriorates and this often leads to night blindness and loss of vision as well.
This is an autosomal recessive disorder which requires the presence of a mutation of both genes. The carrier parents, who carry only one mutation, are healthy. However, their children each have a 25% risk of inheriting this condition.
The diagnosis is most likely made collaboratively by an ophthalmologist and a neurologist. It may require testing by an ERG (electroretinogram), and MRI imaging. No treatment for the disease is known but low vision aids may aid vision. Surgical removal of cataracts could be helpful in selected individuals. Physical therapy may also be of value. Nothing is known regarding the longevity of patients.